Environmental sensor and telemetry systems are used to monitor conditions in a variety of implementations. Temperature, humidity and light sensors are often employed in building control systems to assist in regulating a comfortable environment and/or increasing efficiency in power consumption. Smoke and/or heat sensors provide information regarding a possible hazardous condition.
While current sensing technology has proven adequate for building control systems, there has been an increasing need for sensing devices that are located in small spaces. For example, it is desirable to monitor conditions in animal cages that are used for the housing and care of research animals. However, typical temperature sensor devices and the like are too large to fit conveniently within an animal cage, particularly when several sensor devices are used to monitor various conditions. A further impediment to the use of generally available sensor devices in a cage environment is the significant wiring burden associated with such sensors. Each sensor typically requires wiring for both bias power and for signaling. If multiple sensors are used in an array of cages, the wiring requirements can be staggering.
Accordingly, there is a need for new arrangements for detecting various conditions in relatively small spaces, such as in animal cages, that has a reduced wiring requirement and reduced space requirement.